After Dissipation wore off, I think a simple 10~15 seconds buff that gives you instant cast and no MP cost for Summon I / Summon II will be great. Since the skill already has a long cooldown I don't think this addition will make it too OP, it's just so you don't have to use the Aetherstack gained from it for Energy Drain if you're out of MP and swiftcast your fairy back.